Azo dyes containing a benzo-



United States Patent No Drawing. Filed July 19, 1962, Ser. No. 211,092 9 Claims. ((31. 260-152) This invention relates to monoazo dyes obtainable by coupling various diazo components with seven-membered heterocyclic coupling components variously called benzo-thia-aza-cycloheptadienes or compounds containing the benzothiazepin-one ring.

The coupling components have the following general formula:

wherein R represents a lower alkyl group straight or branch-chained, or a monocyclic aryl group of the henzene series including phenyl, tolyl, chlorophenyl, chloronitrophenyl, nitrophenyl, dinitrophenyl, methoxyphenyl, nitromethoxyphenyl, cyanophenyl, etc. As described in the examples herein, these compounds can be prepared by alternative methods involving either the reaction of o-aminobenzthiol with diketene or acetoacetic esters.

Representative compounds are:

4-methyl-6,7-benzo-,1-thia-5-aza-4,6-cycloheptadiene-2-one 4-pheny1-6,7-benzo 1-thia-5-aza-4,6-cycloheptadiene-Z-one 4- (4-chlorophenyl -6,7-benzo-1-thia-5-aza-4,6-cycloheptadiene-2-one 4- 4-nitrophenyl) -6,'7 -benzo-1-thia-5-aza-4,6-cycloheptadiene-Z-one 4-ethyl-6,7-benzo-1-thia-5-aza-4,6-cycloheptadiene-2-one 4-(4-methoxyphenyl) -6,7-benzo-1-thia-5-aZa-4,6-cyc1oheptadiene-Z-one Theazo dyes obtained by coupling these compounds with various known diazonium compounds have the following general formula:

R at H U \aaw wherein R=lower alkyl such as methyl, ethyl, propyl and butyl,

or aryl as indicated above R'=aryl as indicated above, thienyl or thiazolyl such as S-nitrothiazoyl and 3-nitro-5-acylthienyl Patented Mar. 17, 1964 2 EXAMPLEI 4-Methyl-6,7-Benzo-1-Thia-5-A;a

4,6-Cycloheptaa'iene-2-One In a 1-liter, 3-necked flask, equipped with a dropping funnel, a mechanical stirrer, a reflux condenser, and a nitrogen inlet tube, was placed a solution of 25 grams (0.2 mole) of o-aminobenzenethiol in 400 ml. of benzene. The system was flushed with nitrogen and a nitrogen atmosphere maintained during the reaction. The solution was heated to reflux on a steam bath, and a solution of 16 grams (0.2 mole) of diketene in 50 ml. of benzene added dropwise during 30 minutes. After addition, the reaction mixture was stirred at reflux for one hour, the steam bath removed, and stirring continued while the flask was cooled to 10. The precipitate thus obtained was filtered and recrystallized from ethanol (charcoal). Wt.=13.35 g., M.P. 112-14 (Sw. yield=35%.

EXAMPLE 2 4-Methyl-6,7-Benzo-1-Thia-5-Aza-4,6-Cycloheptadiene- Z-One (Alternate Procedure) In a liter, S-necked flask, equipped with a dropping funnel, a mechanical stirrer, a reflux condenser, and a nitrogen inlet tube, was placed a solution of 50 grams (0.4 mole) of o-aminobenzenethiol in 500 ml. of xylene. The system was flushed with nitrogen, and a nitrogen atmosphere maintained throughout the addition. Stirring was begun and the solution heated to reflux. A solution of 60 grams (0.46 mole) of ethyl acetoacetate in 50 ml. of xylene was added dropwise during 30 minutes, at reflux. The condenser was set for distillation and during the next 45 minutes, 400 ml. of xylene were distilled. The remaining solution was chilled in an ice bath. The solid which precipitated was filtered, dried and recrystallized from alcohol (charcoal). Wt.=12.25 grams, M.P. 113-16" (SW. 108). Concentration of the mother liquor gave a second crop. Wt.=9.75 grams, M.P. 112-15" (Sw. 108), yield=28.8%.

EXAMPLE 3 4 -Ph enyl-6,7-Benzo-1 -Thia-5-Aza- 4,6-Cycl0heptadiene-2-One CH SC II In a 500-ml., 3-necked flask was placed a solution of 26.5 grams (0.22 mole) of o-aminobenzenethiol in 250 ml. of xylene. The solution was stirred, and heated to reflux; then a solution of 45 grams (0.23 mole) of ethylbenzoylacetate in 40 ml. of xylene was added dropwise during 30 minutes, at reflux. After the addition was completed, the solution was stirred at reflux for an additional 15 minutes, then distilled ml. of the xylene. The remaining solution was chilled in an ice bath. A yellow crystalline solid was filtered, dried and recrystallized from alcohol (charcoal). Wt.=10.26 g., M.P. 107-9". Concentration of the mother liquor gave a 3 second crop. Wt.=8.28 g., MP. 1079, yield=33.3%. Analysis.Calcd.: C=71.15%; H=4.35%; N=5.53%; S=12.65%. Found: C=70.58%; H:4.58%; N: 5.74%; S=12.32%.

EXAMPLE 4 Diazotization (A) Nitrosylsulfuric acid was prepared by adding 7.6 g. (0.11 mole) of sodium nitrite portionwise to 50 ml. of concentrated sulfuric acid with stirring and allowing the temperature to rise to 65 C. The solution was then cooled to 5 C. and 100 ml. of a mixture of 15 ml. of propionic acid and 85 ml. of acetic acid was added dropwise with stirring, allowing the temperature to rise to 15 C. and keeping it there during the addition. The reaction mixture was then cooled to 5 C. and 17.25 g. (0.1 mole) of 4-cl1loro-2-nitroaniline was added portionwise while stirring, after which 100 ml. more of the propionic-acetic acid mixture was added, keeping the temperature at 05 C. The reaction mixture was then stirred at 05 C. for 2 hours and the excess sodium nitrite was destroyed by adding 1 g. of urea. The diazotization solution was filtered through a glass funnel and stored in a refrigerator for further use as needed.

Coupling (B) To a solution of 0.76 g. (0.004 mole) of 4-methyl-6,7- 'benzo-l-thia-5-aza-4,6-cycloheptadiene-2-one in 10 ml. of the propionic-acetic acid mixture, cooled to 0 C., was added with stirring 10 ml. (0.004 mole) of the 4-ch1oro- 2-nitrobenzenediazonium solution prepared as in (A) at such a rate that the temperature remained at O C. The coupling mixture was then neutralized to Congo red paper by the addition of anhydrous sodium acetate. After standing in a melting ice bath, with occasional manual stirring, for one hour, the mixture was drowned in 300 ml. of water with stirring. The dye was filtered, washed neutral and dried. The dye weighed 1.34 g. (89.5%). It dyes polyester fibers a deep, bright yellow with good affinity and excellent fastness to light.

The dye prepared as above has the formula C-N: Cl SC N02 EXAMPLE 5 Diazotization (A) In exactly the same manner and using quantities of reagents as in Example 4(A), 8.40 g. (0.05 mole) of 4- methoxy-Z-nitroaniline was diazotized with nitrosylsulfuric acid in propionic-acetic acid solution.

Coupling (B) A solution of 0.38 g. (0.002 mole) of 4-methyl-6,7- benzo-1-thia-5-aza-4,6-cycloheptadiene-4-one in 5 m1. of propionic-acetic acid mixture was coupled with 5 ml. (0.002 mole) of the 4-methoxy-2-nitrobenzenediazonium solution prepared as in (A), by the procedure set forth in Example 4(B). The dye weighed 0.68 g. (92%), and dyed polyester fibers a bright yellow shade with excellent fastness to light.

EXAMPLE 6 Diazotization (A) 18.3 grams (0.1 mole) of 2,4-dinitroaniline was diazotized with nitrosylsulfuric acid in propionic-acetic acid solution, using the same procedure and quantities of reagents as in Example 4(A) 4 Coupling (B) Following the procedure in Example 4(B), 0.38 g. (0.002 mole) of 4-methyl-6,7-'benzo-l-thia-5-aza-4,6- cycloheptadiene-Z-one dissolved in 5 ml. of propionicacetic acid mixture was coupled with 5 ml. (0.002 mole) of the 2,4-dinitrobenzenediazonium solution prepared as in (A). The dye weighed 0.65 g. (yield=84.5%) and dyed poly (1,4-cyclol1exylenedimethylene terephthalate) fibers a deep yellow-orange shade with good light fastness. The dye dyed poly (ethylene terephthalate) fibers a bright yellow with excellent light fastness.

EXAMPLE 7 Diazotization (A) To a solution of nitrosylsulfuric acid prepared by dissolving 0.76 g. (0.011 mole) of sodium nitrite in 5 ml. of concentrated sulfuric acid below 65 C., to which was added 10 ml. of the propionic-acetic acid mixture below 15 C., as described in Example 4(A), was added 2.14 g. (0.10 mole) of 5-amino-4-nitro-2-thienyl isopropyl ketone, below 5 C., followed by addition of 10 ml. more of propionic-acetic acid. After stirring for one hour at 05 C., the excess sodium nitrite was destroyed by addition of 0.1 g. min. and the clear diazonium solution was used immediately.

Coupling (B) Following the procedure of Example 4(B), 0.95 g. (0.005 mole) of 4-methyl-6,7-benzo-1-thia-5-a,za-4,6- cycloheptadiene-Z-one dissolved in 12.5 ml. of propionic acid was coupled with 12.5 ml. (0.005 mole) of the diazonium solution from (A). The dye weighed 1.68 g. (yield is equal to 81%), and dyed polyester fibers a deep golden-brown shade with excellent-to-good light fastness.

The dye has the following formula:

EXAMPLE 8 Following the procedure in Example 4(B), 0.51 g. (0.002 mole) of 4-phenyl-6,7-benzo-1-thia-5-aza-4,6- cycloheptadiene-Z-one dissolved in 5 ml. of propionicacetic acid mixture was coupled with 5 ml. (0.002 mole) of the 4-chloro-2-nitrobenzenediazonium solution from Example 4(A). The dye weighed 0.94 g. (yield=quant.). It dyed polyester fibers a deep, bright yellow shade, with excellent light fastness, but did not dye polyamide fibers.

The dye has the following formula:

(IJaHs EXAMPLE 9 Diazotization (A) 1.38 grams (0.01 mole) of p-nitroaniline was dissolved in a mixture of 1.1 m1. of concentrated sulfuric acid and 2.5 ml. of water; ice (approximately 20 g.) was added, and a solution of 0.76 g. (0.011 mole) of sodium nitrite in 2 ml. of water was added all at once. The mixture was stirred normally until solution was effected; then the excess sodium nitrite was decomposed by addition of 0.2 g. of urea. The resulting solution was filtered from a small amount of impurity and used immediately.

Coupling (B) To an iced solution of 0.95 g. (0.005 mole) of 4- methyl-6,7-benzo-l-thia-5-aza-4,6-cycloheptadiene-2 one is a mixture of 1 ml. of concentrated sulfuric acid and 10 ml. of water was added one half of the p-nitrobenzenediazoniurn solution from (A) (0.005 mole). The coupling mixture was neutralized to Congo red paper with a saturated solution of sodium acetate. After standing for 1 hour, the dye was filtered, washed with water, and dried. The dye weighed 1.62 g. (yield=95.5%). It dyed polyester fabrics a bright yellow shade with good fastness properties.

Other diazotized amines are used for preparing useful dyes as shown in the following table:

Color oi Dye on poly- (1,4-cyc1ohexy1enedimethylene terephthalate) -Fastness to Light Coupling Component Diazonium 4-Methyl-6,7-benz0-1- 2-Ch1oro-4-nitro- Deep greenish-yellow,

thia-5-aza-4,6-cycloaniline. Light fastnessfair. heptadiene-Z-o'ne. 4-Methoxy-2-nitro- Orange-yellow, Light aniline. fastness-good. 2-Amino-5 nitro- Deep lemon-yellow,

phenyl methyl Light iastness-good. sulfone. 2,4-Bismethyl- Lemon-yellow, Light sulfonyl aniline. fastnessgood. 2 Amino-5-nitro- Light russet, Light thiazole. fastnessiair. 4-Chloro-2-nitro- Deep-bright yellow, aniline. Light fastnessexcellent. p-Nitroaniline Deep-bright yellow,

Light iastness-iair. 2,4-Dinitro-anillne Light russet, Light fastness-good. 5-Amino-4-nitro-2- Russet, Light thienyl isopropyl iastnessgod. ketone. 4-Phenyl-6,7-benzo-1- 2,4-dinitroaniline Deep yellow, Light thia--aza-4,6-cyclofastness--good. heptadiene-Z-one. 4-Methoxy-2-nitro- Deep orangeyellow,

aniline. Light fastnessiair. 2,4-Bismethyl- Lemon yellow, Light sultonylanaline. fastness-fair.

What we claim is:

1. Monoazo compounds having the general formula wherein R=a member of the class consisting of lower alkyl and a benzene radical, R =a member of the class consisting of a benzene radical and the radicals R'=a benzene radical 6 3. Monoazo compounds having the general formula R NJ;

(l7N=N-R' wherein R and R each represent benzene radicals.

4. The azo dye of formula 5. The azo dye of formula S (III) 1 10:

6. The azo dye of formula 9. The azo dye of formula No references cited. 

1. MONOAZO COMPOUNDS HAVING THE GENERAL FORMULA 